@charset "utf-8";
/* CSS Document */
* {
    margin: 0;
    padding:0;
}

html {
    font-size : 20px;
}
@media only screen and (min-width: 401px){
    html {
        font-size: 25px !important;
    }
}
@media only screen and (min-width: 428px){
    html {
        font-size: 26.75px !important;
    }
}
@media only screen and (min-width: 481px){
    html {
        font-size: 30px !important; 
    }
}
@media only screen and (min-width: 569px){
    html {
        font-size: 35px !important; 
    }
}
@media only screen and (min-width: 641px){
    html {
        font-size: 40px !important; 
    }
}

header {
	margin: 0 auto;
    padding-top: 1rem;
    padding-bottom: .5rem;
	width: 100%;
    height: 3rem;
    text-align: center;
    background-color: blue;
}

footer {
    position: absolute;
    bottom: bottom;
    margin: 0;
    width: 100%;
    height: 1rem;
    line-height: 1rem;
    text-align: center;
    background-color: rgba(153,153,153,1);
}

#nav {
    margin: .5rem auto;
}
#nav>span {
    height: 1rem;
    line-height: 1rem;
}

#select {
    margin-left: 1rem;
    width: 2rem;
    height: 1rem;
}


#practice {
    position: relative;
    margin: 1em auto;
    margin-top: 2em;
    padding: .5rem;
    width: 12rem;
    height: 4rem;
    background-color: rgba(204,204,204,1);
}

#pra {
    width: 3rem;
    height: 1rem;
    font-size: 1rem;
    vertical-align:middle;
}

.btn {
    position: absolute;
    left: 75%;
    top: 70%;
    width: 2rem;
    height: 2em;
    background-color: rgba(0,153,255,1);
    border-radius: .5rem;
}

.forget {
    margin: 5px auto;
    padding: .5rem;
    width: 12rem;
    min-height: 4rem;
    font-size: .5rem;
    text-align: center;
    background-color: rgba(0,255,255,1);
    color: rgba(255,0,0,1);
    border: 1px solid green;
    -webkit-columns: 5.5rem 2;
       -moz-columns: 5.5rem 2;
        -ms-columns: 5.5rem 2;
         -o-columns: 5.5rem 2;
            columns: 5.5rem 2;
    -webkit-column-rule: 1px solid rgba(0,0,255,.4);
       -moz-column-rule: 1px solid rgba(0,0,255,.4);
        -ms-column-rule: 1px solid rgba(0,0,255,.4);
         -o-column-rule: 1px solid rgba(0,0,255,.4);
            column-rule: 1px solid rgba(0,0,255,.4);        
}

h4 {
    -webkit-column-span: all;
       -moz-column-span: all;
        -ms-column-span: all;
         -o-column-span: all;
            column-span: all;
}